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NEW YORK STATE MUSEUM 



lius limestone were found. This locality is in the town of Phelps, 

 Ontario co. The thin layers in which the fossils occur are said 

 to be directly above the Salina waterlime. The upper limit of 

 the Salina as here given by Hall is not clear, since in Seneca 

 county and at Union Springs the Cobleskill and the Rondout 

 were included in the Salina. The fossils obtained by Hall from 

 this locality were not well preserved, and the figures given are 

 illustrations of typical Manlius limestone fossils from central 

 New York and not of those that were obtained in Ontario 

 county. 



Whatever the stratigraphic relations of these beds may be in 

 the vicinity of Phelps, it is evident that, before the western limit 

 of the county is reached, there is found a stratum similar to the 

 " Bullhead lying directly below the Oriskany or below the Onon- 

 daga, where the Oriskany is lacking, and that it occurs in this 

 position at a number of points between Ontario county and 

 Buffalo, at which it is better known than at any other locality. 



Cobleskill, or " Bullhead " limestone, of Erie county 



The quarries of the Buffalo Cement Co. afford excellent expos- 

 ures of the Cobleskill or " Bullhead " magnesian limestone. The 

 Cobleskill lies directly above the Eurypterus-bearing beds of the 

 Salina and is transitional from them. According to a recent 

 paper by Mr Schuchert 1 there is a hiatus between the Eurypterus- 

 bearing beds of the Salina and the " Bullhead " rock of Erie 

 county. It is very evident however that the rocks between which 

 the hiatus is said to occur are transitional, and that such a hiatus 

 does not exist, nor would one have been considered by Mr Schu- 

 chert had he correlated the " Bullhead " with the Cobleskill 

 instead of with the Manlius. 



The upper surface of the Cobleskill at Buffalo is very irregu- 

 lar, evidently because of elevation and erosion during the interval 

 extending from Cobleskill and lasting till late Oriskany time. 

 Another feature of the Cobleskill at Buffalo is the deep vertical 

 fissures, extending through its entire thickness and well down 

 into the cement beds of the Salina. Attention has already been 

 called to similar fractures in the Cobleskill about Union Springs. 



1 U. S. Mus. Proc. 1902. 26:416. 



